  //
        public void drawCircleArc2(IPoint point,double r)
        {
            IPoint pPoint = point;
            IConstructCircularArc pConstructCirclarArc = new CircularArcClass();//Բ
            pConstructCirclarArc.ConstructBearingRadiusAngle(pPoint,1,false,r,Math.PI);
            ICircularArc pCircularArc = pConstructCirclarArc as ICircularArc;
            ISegment pSegment = pCircularArc as ISegment;
            ISegmentCollection pSegmentCollecton = new PolylineClass();
            object o = Type.Missing;
            pSegmentCollecton.AddSegment(pSegment,ref o,ref o);
            IGeometry pGeometry = pSegmentCollecton as IGeometry;
            IElement pElement = new LineElementClass();
            pElement.Geometry = pGeometry;
            IGraphicsContainer pGraphicsContainer = axMapControl1.ActiveView.GraphicsContainer;
            pGraphicsContainer.AddElement(pElement,0);
            axMapControl1.Refresh();
        }